Have trouble with CMP and relationships

Question

Hello and Thank you for your time.
I'm having a bit of trouble using entity beans and CMP, I'm probably doing some thing wrong. The main problem I am having is with a many to many relationship. Let's say I have the following code:
ClassA.java
@Entity
public class ClassA implements Serializable {
<other variables>
private Collection<Class1> class1Collection;
<other methods>
@ManyToMany(cascade=CascadeType.ALL, mappedBy = "classACollection")
public Collection<Class1> getClass1Collection() {
return class1Collection;
public void setClass1Collection(Collection<Class1> class1Collection) {
this.class1Collection = class1Collection;
Class1.java
@Entity
public class Class1 implements Serializable {
<other variables>
private Collection<ClassA> classACollection;
<other methods>
@ManyToMany
public Collection<ClassA> getClassACollection() {
return class1Collection;
public void setClassACollection(Collection<ClassA> classACollection) {
this.class1Collection = class1Collection;
In the 'other variables' each table has a @Id field and setters and getters for the Id.
This code half works. If I set the collection in ClassA with a Collection of Class1 objects this is populated in to the database and the getClass1Collection method for this also works. If I then try to use the getClassACollection method from a Class1 object the entity manager throws a relationship not complete exception (or some thing to that effect). it is also the case that if I create a list of ClassA objects and place it in to the Class1 objects variable, this does not populate in to the database.
Some thing similar also happens with OneToMany and ManyToOne relationship (only one side of the relationship seems to be part of the relationship)
What am I doing wrong?
Edited by: tehBoris on Mar 26, 2010 1:18 PM

Answer 1

Yes, that's as it should be, but I think the problem is the default for adding the auto page numbers. The default on the top of the dialog box that appears when you choose Auto Page Numbers from the menu says:
Show in Document.
That seems to be the default.  Page numbers in sections won't work with that default. To get it to work, you have to select:
Show in Current Section.
I think I'm right on this, but I'm not sure. I'll have to practice some more. Perhaps this is a default that should be changed in the next version, but I don't know.
Tom